Air bag stem



0613.22, 1940. J` CROWLEY 2,218,639

AIR BAG STEM Filed July 9, 1938 /3 /whm 4a\\\\\\\\\\\\\\1LI|&\\\\\\\\\\\\\ f3 INVENTOR l Z4 B Jmdeva/fr ATTORNEYSPatented Oct. 22, 1940 g UNITED STATES AIR BAG STEM .101m c. Crowley,cleveland'neighis, ohio, assignor to The Dill Manufacturing Company,Cleve land, Ohio, a corporation of `Ohio Application July 9, 1988,serial No. 218,459

5 claims. (o1. 18-45) This invention relates to a stem for an air bag,such as is employed in Vulcaniz'ing rubber tire casings and otherinflatable articles.

The manner in which air bags are'used-in the vulcanization of tirecasings is well understood in the art and Vneed not be explained indetail herein, it being suflicient to say that when the molds containingthe tire casings are arranged in a vulcanizer the air bags are locatedwithin the tire casings and are inated, usually by high temperaturesteam, during the process of curing the tire casings.

Ordinarily the stems of air bags of this character are in the form ofelongated metal stems `having bores extending therethrough and providedat their inner ends with ybases generally of oval or circular formation.The stems are molded into the bags or they have rubber molded aroundthem and then this rubber with the stems therein is molded into the airbags. f

In the use of an air bag equipped with the ordinary or conventional stemand when steam is used to inflate the air bag during the curing of thetire casing, heat is transferred through the metal stem to the rubber ofthe bag in which the stem is vulcanized, and results in a rapiddeterioration ofthe rubber with consequent leaks occurring between theoutside of the stem and the rubber of the air bag.

The object of the present invention is to provide a stem for an air bagwhich is so constructed as to substantially reduce the deterio-rationlof the rubber of the bag in which the rstem is molded.

A further object is to provide a stem for an air bag which is soconstructed as to have a maximum surface for bonding the rubber of thebag to the stem and also which is'so constructed that a minimum amountof heat is transmitted to theA rubber of the bag adjacent' tothe stemwhenhigh temperature steam is being passed through the stern during thecuring of the tire casing.

A further object is to provide an air bag and stem assembly such thatthe number ofY cures which can be made with the bag will be materiallyincreased.

Further and additional objectsy and advantagesv Fig. 1 is a vfragmentarysectional view of an V*air bag having'mounted therein one form of stemvduring the curing of the tire casing.

embodying the invention, the stem being shown partly in elevation andpartly in section.

Fig. 2 is a view similar to Fig. 1 but illustrating a different form ofthe invention.

Fig.f 3 is a sectional view taken substantially on line 3 3 of Fig. 1looking in the direction of the arrows, and l Fig. l is a sectional Viewtaken substantially on line 4-4 of Fig. 2 looking in the direction ofthe arrows.

A portion of a rubber air bag shown in section in Fig. l, is indicatedat I and this bag is provided with a thickened boss-like part I I inwhich the bag stem is vulcanized. The stem shown in Figs.` 1 and 31sformed of metal and has an externally threaded outer end I2 locatedexteriorly of the air bag andA a reduced inner end portion I3 that ismolded in the rubber of the air bag and is provided at its inner endwith exterior threads I4. The portions I2 and I3 of the stem areprovided with a continuous bore I5 therethrough and by means of whichhigh temperature steam can be introduced into the air bag A base memberI6 which may be of any desired configuration and which is provided witha central threaded' opening is screwed upon the threaded inner end ofthe portion I3 of the stem and is molded into the rubber of the air bagwhen the stem is molded therein.

' A hollow metal shell I1 is associated with the lstem and molded intothe rubber of the air bag.

'Thevl'iollow metal shell in this instance is preferably of relativelythin gauge metal and is provided at its upper or outer end with aninturned ange I8 contacting the inner end of the exteriorly threadedportion I2. and also the eX- terior surface of the reduced portion I3 ofthe stem. The hollow metal shell Il, clue to the inwardly extendingflange I8 and to the configuration of the shell, is spaced from thereduced portion I3 of ythe stem and this shell is preferably permanentlyattached to the stem and is provided at its lower or inner end with anoutwardly extending flange I9. The shell Il is insulated from theportion I3 ofthe stem by the rubber'of the air bag located between theshell and the stem, as clearly shown in Fig. 1.

The stem consisting of the portions I2 and I3, base I6 and shell I'Iconstitutes a unit such that vthe portion yI3 of the stem together withthe base I6 and shell I1 canl be molded into the rubber of the air bag.y

It will be seen that an improved bond can be obtained between the stemand the rubber of the air bag, since the outside and inside surfaces ofthe shell I 'I and the surfaces of the flanges I8 and I9 provideadditional vulcanizing areas.

Also it will be noted, as referred to previously, that the shell I'I isinsulated from the portion I3 of the stem by the rubber lying betweenthe shell and the portion I3 and thus the shell I'I and the rubberbonded thereto are protected from the heat transferred through the wallof the portion I3 of the stem, with the result thatthe bond between therubber of the air bag and the vulcanizing areas of the shell Il is notdestroyed because of excessive heat.

An air bag provided with a stem structure of the character explained canbe used for a greater number of curing operations than could an air bagprovided with the conventional stem, since the bond between the rubberofthe bag and the vulcanizing areas of the stem, base and shell is notreadily destroyed because of excessive heat, and consequently leaks donot occur as readily as is the case with air bags employing the usualtype of stems.

In Figs. 3 and 4 of the drawing there is illustrated a somewhat modifiedform of stem embodying the invention. The stemshown in these figures islonger than the stem shown in Figs. 1 and 2 and is provided with aportion indicated by the numeral 2i), which is located exteriorly of theair bag and is externally threaded, and with a reduced portion 2|located within the rubber of the air bag, and also externally threaded,as indicated at 22, to provide surfaces which will interlock with therubber of the bag when the stem is vulcanized therein. Intermediate theportions 20 and 2l of the stem is an annular shoulder portion 23 which,when the stem is mounted in the air bag, is likewise molded into therubber of the bag. The entire stem is provided with a bore 24 extendingtherethrough.

In this form of the invention the stem instead of having a separate baseand shell memberis provided with a single member for performing thefunctions of the base and shell member. In this instance the singlemember referred to is of general circular configuration and isexteriorly threaded, as indicated at 25, to provide surfaces forinterlocking with the rubber of the bag, it being noted that the upperend of the member is of inwardly tapered or conical formation asindicated at 2li. The conical or tapered upper end 26 of the membercontacts the shoulderl 23 and the portion 2l of the stem and ispreferably permanently connected to the stem by suitable means. It willalso be noted that the member is of such size, with respect to theportionv 2l of the stem, that its interior wall surface is spacedoutwardly of the outer surface of the` portion 2i of the stem, whereforethe rubber of the b ag will extend between the member and the portion 2lif the stem.

The inner end of the threaded portion 25 of the member is provided withan outwardly extending flange 21 which constitutes` in effect a base forthe stem, and said iiange is likewise provided with serrations orythreads forming surfaces that interlock with the rubber of the air bag.

In the form shown in Figs. 2 and i the portion 2i of the stem, shoulderand the member secured thereto are first molded into a mass oi rubber,indicated at 28, and then this mass of rub-ber is molded into the rubberof the air bag I. However, when the parts are fully united the rub-ber26 and the rubber of the air bag will in effect constitute an integralrubber wall structure.

It will be seen that, as in the first described embodiment, the membersecured to the portion 2l of the stem and the rubber bonded thereto areinsulated from the stem by the rubber lying between the member and saidportion of the stem in the same Way as was the shell il and the rubberbonded thereto. In this last described form additional vulcanizing areasare provided, thus improving the bond between the rubber of the bag andthe surfaces of the stem and member, with a resultant improvement in thelife of the bag for the reasons set forth with respect to the firstdescribed form.

Although specific embodiments of the invention have been illustrated anddescribed herein, it will be understood that the invention issusceptible of various modifications and adaptations within the scope ofthe appended claims.

aving thus described my invention, I claim:

1. A stem for an air bag of the character described, comprising asubstantially tubular stem proper having a bore therethrough andprovided with a portion adapted to be molded into the material of theair bag, and a member mounted on said stem and surrounding said portionthereof in spaced relation thereto, said member being of va lengthsubstantially coextensive with the length of said portion.

2. A stem for an air bag of the character described, comprising asubstantially tubular stem proper having a bore extending therethroughand provided with a portion adapted to be molded into the material ofthe air bag, and a relatively thin metallic shell mounted on said stemand surrounding said portion thereof in spaced relation thereto, saidshell being oi a length substantially coextensive with the length ofsaid portion.

3. A stem for an air bag of the character described, comprising asubstantially tubular stem proper having a bore therethrough andprovided with a portion adapted to be molded into the material of Ithebag, and a substantially hollow member surrounding said portion of thestem in spaced relation thereto and having one of its ends shaped tocontact said stem and be secured thereto while its opposite end isprovided with an outwardly extending fiange, said member being of alength substantially coextensive with the length of said portion.

4. A valve stem for an air bag of the character described, comprising astem proper having an enlarged portion` adapted to be arrangedexteriorly of the air bag and a reduced portion separated from saidenlarged portion by a shoulder and adapted to be molded in the materialof the air bag, andA a hollow member surroundingsaid reduced portioninspaced relation and having one ofits ends shaped to contact saidshoulder and its opposite end provided vwith an outwardly extendingflange, said member being substantially coextensive in length with thelength of said reduced portion. I

5. A stem for an air bag of the character described comprising asubstantially tubular stem proper having a bore therethrough andprovided with a portion adapted to be molded into the material of theair bag, and a member mounted

